Retrievable gas lift apparatus



Sept. 11, 1962 c. B. WRIGHT, JR., ETAL 3,053,323

RETRIEVABLE; GAS LIFT APPARATUS 4 Sheets-Sheet 1 Filed Aug. 3l, 1959 df. S ,t R ,0 0 www ffm WLM BM s /eo rs aa CM BY 'jf/@2% A Traa/gf! Sept. 11, 1962 c. B. WRIGHT, JR., ETAL 3,053,323

RETRIEVABLE GAS LIFT APPARATUS 4 Sheets-Sheet 2 Filed Aug. 31, 1959 6 6 o H ,n M n Z M 6 6 l! u s. M 7g as ,0a

INVENTORS Sept. 1l, 1962 c. a. WRIGHT, JR., ETAL 3,053,323

RETRIEVABLE: GAS LIFT APPARATUS Azrae/vsx 3,053,323 IIE'I'RIEVABLE GAS LIFT APPARATUS Charles I3. Wright, Jr., and Mason M. Lilly, Houston, Tex., assignors, hy mesne assignments, to Harold Brown Company, a corporation of Texas Filed Aug. 31, 1959, Ser. No. 837,029 12 Claims. (Cl. 166-224) This invention relates to apparatus including a gas lift valve insertable into and retiievable from oil well tubing without removing the tubing from the well. The invention provides apparatus slidable within the well tubing and responsive to action initiated at the surface to lock itself into place at any desired depth. In addition, sealing means are provided which are readily set at a desired location within the well tubing.

In the production of so-called non-flowing oil wells, those in which the natural pressure on the subsurface liquids is insufficient to litt them to the surface, a technique of artificial lifting by gas pressure has been developed. This method of production requires the use of one or more gas lift valves positioned at appropriate elevations within the well to admit gas under pressure into the tubing from the annulus between the well casing and tubing. The need for such artiiicial production means ordinarily does not arise until some time after the well has been placed in operation, and the adaptation oi the well tubing for gas lift production has heretofore necessitated several time-consuming operations. For example, it is necessary with current gas lift apparatus to interpose gas litt valve mandrels or special sections of tubing throughout the string. These manndrels provide points of attachment for gas lift valves, and also provide prepared openings through which the valves may introduce gas into the tubing. As such mandrels form a part `of the tubing string, it is necessary to make up the assembly at the well head as the string is assembled.

The present invention contemplates the elimination of much of the preparatory work necessary for introduction of gas lift apparatus, it being necessary only to lower the self-anchoring gas lift device to the vicinity of a perforation in the production tubing already in the well, and lock it into position.

Accordingly, it is an object `of this invention to provide a self-anchoring gas lift device which may be secured at a desired point in the tubing of a subsurface well.

It is a further object to provide a self-anchoring gas lift device which may be operated from the surface to lock itself at a desired point within a well, and which subsequently may be released and removed by a surface initiated action.

Another object is to provide a self-anchoring gas lift device having spaced seals for sealing above and below an aperture in the well tubing.

Still another object is to provide apparatus for supporting a gas lift valve within a tubing string at a desired point and for introducing gas and well liquid to the valve.

Yet another object is to provide an improved sealing device for well tools.

Another object is to provide improved anchoring apparatus for anchoring Well tools inside a well conduit.

These and other objects of this invention will become more apparent upon consideration of the following description and the attached drawings, wherein FIGURE l is a view of one embodiment of the apparatus of this invention supporting a gas lift valve inside a string of tubing in a well bore, the tubing, casing, and well being shown in vertical section,

FIGURE 2 is a vertical sectional view of one embodiment of the anchoring apparatus of this invention, the slips being shown in released position,

FIGURE 3 is a horizontal sectional view of a portion tent of the anchoring apparatus of FIGURE 2 taken at line 3 3 of FIGURE 2,

FIGURE 4 is a vertical sectional view of the anchoring apparatus shown in FIGURE 2, the slips being shown in engaged position,

FIGURE 5 is a vertical sectional view of one type of gas lift valve which may be used in the apparatus of this invention,

FIGURES 6A, 6B, and 6C together comprise a vertical sectional view of one embodiment of the packoff and gas admission portion of the apparatus of this invention, and

FIGURE 7 is a horizontal sectional view of the novel detent means shown in FIGURE 6A, taken at line 7 7 of FIGURE 6A.

FIGURE 1 shows the entire tool string itl as it is positioned in a string of tubing I2 inside well casing I4. The retrievable gas lift apparatus is lowered on the end of a wire line, and comprises anchoring apparatus I6, a gas lift valve I8, a packoff and gas admission assembly 2li, and a bottom stop assembly Z2. Generally a check valve 24 is also included in the assembly.

Referring now to FIGURE 2, the anchoring apparatus I6 comprises an upwardly and inwardly tapered expander cone 26 on which slip segments 28 are adapted to ride. Expander cone 26 has a threaded axial bore Btl into which socket head cap screws 32 and 34 are screwed. Between the head 36 of cap screw 32 and the small end of expander cone 26 a shouldered sleeve 3S extends. It will be appreciated that sleeve 38 and cap screw 32 may be unitary, and that the embodiment shown is used for economy in manufacture. The combination of elements 26, 32, 34, and 38 comprise a body member for the anchoring apparatus. A fishing neck 40 is slidably retained on sleeve 3S by shoulder 42. Fishing neck 40 has an end collar 44 for engagement with a conventional wire line iishing tool.

Slip segments 28 each have an internal longitudinal dovetail slot 46, which engages a screw head 48 on expand-er cone Z6. The upper end of each slip segment is formed with an outwardly extending T Si). Fishing neck 40 has an enlarged lower end 52 and a transverse T-slot 54 in its lower ace for engagement of the T 50 on the upper end of each slip segment. -A shear pin 56 extends transversely across iishing neck 4@ above head 36 of cap screw 32 to retain the slips in unexpanded position while lowering the tool into the hole.

`Cap screw 34 is adjustably secured to expander cone 26 by jam nut 58. Slip release body 6I) is slidably fitted around the shank of cap screw 34 and encloses its head 62. A sub 64 provides means for attachment of other tools. A shear pin 66 extends transversely of slip release body 60 below the head 62 of cap screw 34.

FIGURE 2 shows the slips in collapsed position. To expand the slips into engagement with the bore of the tubing, as shown in FIGURE 4, a sharp blow or jar is applied to collar 44 of fishing neck 40, thereby shearing shear pin 56 and allowing slip segments 28 to move downwardly and outwardly on expander cone 26 into engagement with the tubing. Screw head 48 in dovetail slot 46 guides the slip segments into proper alignment with the tubing bore to insure that the slip segments contact the tubing solidly.

As shown in `FIGURE 5, gas lift Valve I8 is attached to the lower end of sub 64. The gas lift valve shown and described herein is merely a preferred type, it being apparent that other designs may also be used. In this preerred embodiment, a spring housing 63 is threadedly attached to sub 64, an O-ring 70 being used to provide a seal at the threaded connection. Spring housing o8 is in turn threadedly attached to a barrier member 72, 0-ring '74 providing a seal at this connection. Valve housing 76 is threadedly attached to the barrier member 72, and in turn attached to a check valve 24 therebelow. Valve housing 76 has a gas inlet bore 80 forming an internal shoulder 82. A removable valve seat 84 is positioned against this shoulder, an O-ring 86 forming a seal between the valve seat and the bore 88 of the Valve housing 76. Gas outlet apertures 89 are provided in the wall of the valve housing just above valve seat 84. A ball valve 90 is adapted to seal against valve seat 84 and close off gas inlet bore 80. Ball valve 90 is attached, as by welding, to valve rod 92, which in turn is threadedly attached to head 94. Head 94 comprises an enlarged portion of upwardly extending push rod 96. On the upper end of head 94 the lower end of a bellows 98 is sealingly attached, surrounding push rod 96. The upper end of bellows 98 is sealingly attached to barrier member '72. Push rod 96 extends upwardly through axial bore 160 in barrier member 72 and terminates in a reduced diameter 102. A spring washer 104 slidingly engages reduced diameter 102 of push rod 96, and the lower end of a compression spring 106 bears against the spring washer. The upper end of spring 106 bears against adjusting nut 108 threadedly engaged in the bore of spring housing 68. Iam nut 110 locks the spring nut in place.

A gas lift valve shown and described herein is of the so-called fluid-operated type, i.e., the opening of the valve to admit gas is governed by the pressure of the well fluid on the valve, as opposed to gas-operated valves, which `are opened by gas pressure. The use of a uid-operated valve is highly advantageous, since it opens only when a predetermined head of fluid is above the valve, thus reducing considerably the amount of gas used in the gas lift operation.

Below gas lift valve 18 a check valve 24 to allow flow vertically upwardly therethrough but prevent flow downwardly, is generally provided. Such valves are well known in the art, so that no detailed description is necessary here. This check valve prevents back flow of well fluid into the annulus between the tubing and the casing.

Referring now to FIGURES 6A and 6B, it will be seen that the packoff and gas admission assembly is threadedly attached to the lowel end of check valve This assembly comprises an upper hollow body 112, a slidably mounted sleeve 113 comprising upper and lower sleeve sections 114 and 116, and a lower hollow body 118. It is apparent that sleeve 113 could be made unitary, but the structure shown is preferred because it allows a wider range of applications of the tool, as will become apparent hereinafter. 0rings 119 provide sealing engagement of the sleeve sections and the body members.

Surrounding each upper body 112 and lower body 118 is an annular expansible seal unit 126. Each seal unit comprises an annular exible cup member 122 and an annular restraining shell 124. Restraining shell 124 has a U-shaped cross-section, within which one edge of the cup member 122 is fitted in tight engagement. The other edge of the cup member is spaced outwardly of the body. In the bottom of the U Iare `a plurality of small apertures 126 which are provided to allow flow of air and other gasses from shell 124 during fabricating and molding of the seal unit, so that no voids are left in the shell. Cup member 122 is made of a flexible, resilient oil-resisting material, such as Hycar or sirnil-ar synthetic rubbers.

Seal unit 120 is retained on each of bodies 112 and 118 between an annular shoulder 126 and snap ring 12S. A backup ring 130 is also provided to give full support to shell 124 of seal unit 120. An O-ring 132 provides a seal between each seal unit and its corresponding body to prevent leakage therethrough.

The usual unrestrained sealing cups have not been found satisfactory `for this service, because gas pressure between the seals forces the inside surface of the seal away from the body, thereby allowing leakage past the seal. In addition, the synthetic rubbers usually used, bein; incompressible, will flow under pressure, so that they become deformed. By enclosing the small end of the cup on three sides, and providing an O-ring seal between the cup and the body, these deficiencies of the prior art seals are eliminated.

The ends 134 of sleeve 113 are tapered, thereby providing expansion means for the corresponding seal units 120. The tapered ends 134 are releasably retained out of engagement with seal units by yieldable means between the ends of sleeve 113 and the upper and lower bodies, which means resist movement of the bodies toward each other. The yieldable means includes a plurality of detents 136, which may be of the spherical form shown, which are positioned in apertures 138 substantially equally spaced circumferentially around each of the sleeve sections. A band-shaped spring 140 lies in a circumferential groove 142, surrounding and retaining detents 136, and biasing them radially inwardly. The ends of the spring are spaced apart, `as shown in FIGURE 7, and a pin 144 between the ends prevents the spring from moving circumferentially around the sleeve on which it is mounted.

The detents 136 are biased radially inwardly against the bottom of a groove 146 circumscribing each body 112, 118. One wall 148 of the groove 146 is bevelled out f to a reduced diameter portion 150, the depth of groove 146 on this side being less than the radius of detent 136, so that axial force will cause detents 136 to expand spring 140 and move out of groove 146 onto reduced diameter portion 150.

Reduced diameter portion 150 provides a circumferential passageway 152 between body 112 and sleeve 113. Apertures 154 in sleeve 113 communicate outwardly therefrom into the space between seal units 120, and aperture 156 communicates inwardly therefrom. Aperture 156 forms the lower end of a gas conduit 158, which extends upwardly therefrom into sealing engagement with the upper end of body 112, thereby communicating with check valve 24.

Apertures 160 in body 112 just above upper seal unit 120 provide communication between the interior of the packoif and gas admission assembly and the well tubing above this assembly, so that well fluid may flow upwardly therethrough.

Reduced diameter portion 150 in lower body 118 provides a circumferential passageway 153 between body 118 and lower sleeve section 116. An aperture 15S in sleeve section 116 communicates outwardly from passageway 153 into the space between seal units 120. When the tool is set in position, as hereinafter described, and gas pressure is applied to the annulus between the seals 120, this gas is allowed to ilow through apertures 154 and 155 into circumferential passageways 152 and 153, and then to pass between sleeve section 114 and upper body 112, and between sleeve section 116 and lower body 118, to assist in the expansion of seal units 120 and thereby result in increased contact and better sealing between the seal units and tubing 12.

Attached to the lower end of lower body 118 and extending downwardly therefrom is a bottom stop assembly comprising stop assembly body 162 having a reduced diameter 164 intermediate its ends. A collar 166 is slidably mounted on reduced diameter 164 and supports one end of each of a pair of resilient dog arms 168, each of which has a dog on its lower end. A dog retainer spring 172 is pivotably attached to each of the dogs 170.

In operation, the well tubing is first perforated at 174 above any desired tubing collar 176 (FIGURE 6). The apparatus of this invention is then assembled in the order shown in FIGURE 1, and lowered into the tubing string on a wireline, by means of a conventional overshot. While lowering, each dog retainer spring 172 is secured around the opposite dog 170, and collar 166 is adjacent the lower end of reduced diameter 164, so that resilient dog arms 168 are held inwardly and dogs 170 are retained out of engagement with the bore of the well tubing.

When the lower end of the tool passes tubing collar 176 just below perforation 174, downward movement is stopped, and the tool is pulled upwardly so that the ends of springs 172 engage the tubing end within collar 176. Upon further upward movement, springs 172 are pushed olf the dogs, which are thereby released. The tool is then moved downwardly again until the dogs engage the recess between the tubing ends. The overshot is then released and a bumper sub or other jarring means used to drive downwardly on collar 44 of fishing neck 4t). The jarring action causes detents 136 to be disengaged from grooves 146, so that the tapered ends 1134 of sleeve 113 slide into engagement with the inside of seal units 120 to expand cups 122 outwardly and seal oi the space between the seal units.

Additional jarring then shears shear pin 56, causing slip segments 28 to slide down expander cone 26 and engage the bore of the tubing. These slips are necessary to prevent well pressure from blowing the tool out of the Well. The tool is now ready for operation.

Generally a number of tools of this invention will be placed in a tubing string, the lowest tool being placed below the surface of the well fluid in the tubing, and other positioned at intervals thereabove. Natural gas or air under pressure is fed down the annulus between the tubing and the casing, passes through aperture 174 in the tubing, through apertures 154 in sleeve 113, and through gas conduit 158 and check valve 24 to -gas inlet bore 80 of gas lift valve 18. The valve spring adjusting nut 108 has been adjusted to put suicient tension on spring 106 to prevent gas pressure alone from opening valve 90.

Well fluid rises, under formation pressure, through stop assembly body 162, lower body 118, sleeve 113, and upper body 112, and passes to the annulus between the tubing and the tool through apertures 160; The well fluid continues to rise to some point above gas outlet apertures S9 of the lowest gas lift valve. The pressure exerted by this head of well tluid against head 94 and bellows 98 of the gas lift valve causes the valve to open. The setting of spring adjusting nut 108 determines the head of well uid required to open valve 90. When the valve is opened, a surge of gas flows through and out apertures 89 and raises the fluid in the well to the next higher valve, where the process is repeated.

When it is desired to remove the tool from the well, a sharp blow is delivered to the head 36 of cap screw 32. The force of this blow is transmitted through expander cone 26 and cap screw 34 and shears shear pin 66, thereby allowing expander cone 26 to move downwardly and free slip segments 28. An overshot is then engaged with collar 44 and an upward force exerted. Upper body 112 of packoi and gas admission assembly is thereby moved upwardly, disengaging tapered sleeve end 134 from upper cup 122 so that the cup is allowed to contract, and detents 136 snap into groove 146. -Further pulling similarly releases the lower seal unit, and pulls dogs 170 out of engagement at the tubing collar. Thus the entire tool, including the stops, may be pulled with one continuous motion.

The various novel components of the apparatus just described obviously have many applications other than in conjunction with gas lift valves. For example, by omission of the gas lift valve and addition of another lower packoif assembly, a tubing patching tool is obtained. The use of a sectional sleeve allows the insertion of a conduit section of any desired length to encompass a series of perforations in the well tubing. The particular stop assembly used is attached to the tool, whereby it may be lowered and xed into position when the tool is lowered into the well, and may be pulled out of the well along with the tool, so that it is not necessary to make a second run into the well to position or retrieve the stop.

A preferred embodiment of this invention has been shown and described herein. Many modilications thereof will be apparent to those skilled in the art, therefore the invention is not limited to the preferred embodiment, but only as set forth by the following claims.

We claim:

1. Gas lift apparatus insertable into and retrievable from a well tubing string comprising tubular upper and lower bodies, a sleeve slidably connecting said upper and lower bodies in longitudinally movable spaced relationship, means intermediate said sleeve and each of said upper and lower bodies for limiting relative longitudinal movement therebetween, means carried by the lower body cooperable with the well tubing string tot stop downward movement of the apparatus, a resilient, expansible seal carried about each of said upper and lower bodies, tapered cam means on said sleeve adapted to expand said seals radially outward into engagement with said well tubing in response to relative longitudinal movement of said bodies in one direction, a tirs-t aperture in the wall of said upper body in communication with the space between said seals, a conduit communicating between fthe upper end of said upper body and said first aperture, a second aperture in the wall of said upper body above the seal about said upper body, a gas lift valve above said upper body, conduit means connecting the upper end of said upper body to said gas lift valve, and anchoring means mounted on the upper body insertable into said well tubing string adapted -to anchor all the aforesaid apparatus to prevent vertical movement in the tubing.

2. Gas lift apparatus as Idefined by claim l wherein said anchoring means comprises an anchor body attached to the upper end of the gas lift valve, an upwardly and inwardly tapered surface on said anchor body, -a longitudinally slidable tubular member carried about said anchor body above said tapered surface, and anchor slips longitudinally slidably engaged with said tapered surface and carried by said tubular member and radially movable relative thereto in response to longitudinal movement along said tapered surface.

3. Gas lift apparatus insertable into and retrievable from a well tubing string comprising a packoi and gas admission assembly, said assembly comprising tubular upper and lower bodies, a sleeve slidably connecting said upper and lower bodies in longitudinally movable spaced relationship, means intermediate said sleeve and each of said upper and lower bodies for limiting relative longitudinal movement therebetween, means carried by the lower body `cooperable with the well tubing string to stop downward movement of said pack-olf assembly, a resilient, expansible seal carried about each of said upper and lower bodies, and tapered cam means on said sleeve and adapted to expand each of said seafls radially outward into engagement ywith said lwell tubing in response to relative longitudinal movement of said bodies in one direction, whereby a packed-oit annulus is formed exteriorly of said sleeve; a gas lift valve attached to said packoff and gas admission assembly; and means in said assembly communication between said packed-olf annulus and said gas lift valve.

body.

6. Gas lift apparatus as dened by claim 5 and including yieldable means between said sleeve and each of said upper and lower bodies adapted to resist movement of said bodies in said one direction.

7. Gas lift apparatus as deined by claim 6 and including a lower stop member attached to said lower body and adapted to be lowered into said well tubing string along with said apparatus and to be set to prevent downward movement of said lower body and removable with said apparatus, and anchoring means attached to said gas lift valve adapted to be set to prevent upward movement of said apparatus.

8. Gas lift apparatus as defined by claim 7 wherein said anchoring means comprises an anchor body att-ached to the upper end of the gas valve, an upwardly and inwardly tapered surface on said anchor body, a longitudinally slidable tubular member carried about said anchor body above said tapered surface, and anchor slips longitudinally slidably engaged with said tapered surface and carried by said tubular member and radially movable relative thereto in response to longitudinal movement along said tapered surface.

9. Anchoring means comprising an anchor body having an upper end and a lower end, an upwardly and inwardly tapered surface on said anchor body, a longitudinally slidable tubular member carried about said anchor body above said tapered surface, anchor slips carried by said tubular member and radially movable relative thereto in response to longitudinal movement of said tubular body in a setting direction, a slip release body slidably mounted on said anchor body below said tapered surface, means on said `anchor body limiting the relative longitudinal movement of said slip release body, `and a shear pin in said slip release body adapted to be sheared upon movement of said anchor body in a releasing direction.

l0. Anchoring means for resisting upward movement of a well tool supported in a well conduit comprising a body member having an upper head portion, an upper shank portion, an upwardly tapering expander cone portion, a lower shank portion, and a lower head portion, a fishing neck slidably retained on said upper shank portion by said upper head portion, said shing neck extending upwardly beyond said upper head portion, a shear pin extending transversely of said fishing neck above said upper `head portion, a transverse T-slot in the lower end of said lfishing neck, a plurality of slip segments carried in said T-slot, said slip segments extending downwardly therefrom and overlying said expander cone portion and adapted to be moved radially relative thereto in response to downward movement of said shing neck With respect to said expander cone portion, a hollow releasing body longitudinally slidable on said lower shank portion and extending below said lower head portion, a shear pin extending transversely of said releasing body below said lower head portion and adapted to be sheared by said `lower head portion upon relative downward movement thereof, `and means on said releasing body for connection to said well tool.

11. An expansible seal unit comprising a exible annular cup member, means within said cup member for eX- panding one edge of said cup member, an annular shell having a U-shaped cross-section enclosing the other edge of said cup member, a plurality of apertures in the closed end of the shell, and circumferential sealing means on the inside circumference of said shell.

12. Gas lift apparatus insertable into and retrievable from a well tubing string comprising anchoring apparatus at the upper end of said gas lift apparatus for anchoring said gas lift apparatus in said well tubing against upward movement relative thereto, a gas lift valve attached to said anchoring apparatus, a packof and gas admission assembly attached to said glas lift valve, and a bottom stop assembly attached to said packof and gas admission assembly for anchoring said packoff and gas admission assembly in said well tubing against downward movement relative thereto; wherein said anchoring apparatus comprises a body member having an upper head portion, an upper shank portion, an upwardly tapering expander cone portion, a lower shank portion, and a lower head portion, a fishing neck slidably retained on said upper shank portion by said upper head portion, said fishing neck extending upwardly beyond said upper head portion, a shear pin extending transversely of said fishing neck above said upper head portion, a transverse T-slot in the lower end of said fishing neck, a plurality of slip segments carried in said T-slot, and extending downwardly therefrom and overlying said expander cone portion and adapted to be moved radially relative thereto in response to downward movement of said fishing neck with respect to said expander cone portion, a hollow releasing body longitudinally slidable on said lower shank portion and extending below said lower head portion, a shear pin extending transversely of said releasing body below said lower head portion and adapted to be sheared by said lower head portion upon relative downward movement thereof, and means on said releasing body for connection to said gas lift valve; and wherein -said packoff and gas admission assembly comprises tubular upper and lower bodies, conduit means connecting the upper end of said upper body to said gas lift valve, a sleeve slidably connecting said upper and lower bodies in longitudinally movatble spaced relationship, means intermediate said sleeve and each of said upper and lower bodies for limiting relative longitudinal movement therebetween, a resilient, expansible seal carried about each of said upper and lower bodies, tapered cam means on said sleeve adapted to expand said seals radially outwardly into engagement with said Well tubing in response to relative longitudinal movement of said bodies toward each other, cooperating gas apertures in said sleeve and in said upper body, a gas conduit commur nicating between the aperture in said upper body and the 4upper end of said upper body, a well uid aperture in the upper body `above the seal therearound and communicating between the interior of the upper body and the interior of the well tubing surrounding and above said upper body, and means on said lower body for attaching said bottom stop assembly.

References Cited in the file of this patent UNITED STATES PATENTS Wall et al Ian. 26, 1960 

